Senior Network Engineer

Who we are

We are a leader in mobile technology, providing innovative solutions to 1.2 billion consumers. In an ever-increasing digital world, we help businesses grow their digital reach & toolkits to optimize user experience, increase engagement, attract new customers, and boost their revenues.
Think of performance marketing but on steroids as our top-notch marketeers and engineers build digital journeys through an omnichannel marketing approach like no other. Currently, we work with the biggest names in Telco, Insurance, Education, FMCGs, and Retail in over 45 countries in Latin America, Africa, the Middle East, and South-East Asia.

About the role:

We are looking for a strategic and highly technical Senior Network Engineer to join our team in Athens.

In this role, you will contribute your specialized expertise, technical skills, and industry best practices to a team of highly skilled network professionals. You will play a key part in supporting and optimizing mission-critical LAN and WAN infrastructures, demonstrating strong technical competence, persistence, and a structured, analytical approach to problem-solving. You will bridge the gap between traditional networking and modern software-defined environments, providing mentorship to junior engineers and driving high-impact architectural initiatives.

What you will do...

• Technical Leadership & Mentorship: Act as a lead for complex projects; provide technical guidance and mentorship to mid-level and junior engineers to foster a culture of continuous learning.
• Infrastructure Architecture: Design, implement, and evolve resilient LAN/WAN and Data Center architectures (Cisco Nexus, VPC) that align with business growth.
• Network Automation: Drive operational efficiency by implementing automation techniques (e.g., dynamic routing link backup).
• Security & Compliance: Lead the hardening of network security postures. Manage Next-Gen Firewalls (Fortinet, Check Point, FortiGate, NAC (Aruba ClearPass/Cisco ISE), and Zero Trust frameworks.
• Lifecycle Management: Proactively manage the lifecycle of network assets, including capacity planning, security advisories, firmware orchestration, and performance tuning.
• Cloud Integration: Design and manage hybrid-cloud connectivity (AWS/Azure/GCP), ensuring seamless integration between on-premise data centers and cloud VPCs.
• Escalation Support: Serve as the final escalation point (L3) for complex network outages, participating in an on-call rotation to ensure 24/7 service availability.

• Vendor & Stakeholder Management: Collaborate with external vendors and internal DevOps/System teams to integrate network solutions.

Requirements:
• 8+ years of hands-on experience in enterprise-grade network environments.
• BSc/MSc in Computer Science, Network Engineering, or a related field.
• Core Networking: Expert-level command of switching and routing protocols (BGP, OSPF, EIGRP, STP, LACP, HSRP).
• Network Security: Deep expertise in NGFW (FortiGate, Check Point, Cisco ASA / FTD), VPN technologies (IPsec, SSL), and SD-WAN implementation.
• Wireless & Access Control: Advanced knowledge of Enterprise WiFi (Aruba Central) and Identity Management (ClearPass or Cisco ISE).
• Application Delivery: Experience with L4-L7 Load Balancing (F5 BIG-IP LTM) and Web Application Firewalls (F5 Big-IP AWAF/FortiWeb).
• Cloud & Virtualization: Proven experience with Cloud Networking (VPC, Subnetting, Network ACL/Security Groups, Site-to-Site VPN with on-premises DCs, ExpressRoute) and Virtualization (VMware NSX, VRFs, VDOMs, VSX, FPR).
• Certifications: Professional level certification (e.g., CCNP, NSE 4-7, CCSA-CCSE) are required; Expert level (CCIE) is a significant plus.

What makes you a great fit:

• Strategic Thinker: You look beyond the immediate "fix" to understand the long-term architectural impact.
• Resilient: You remain calm and analytical under pressure, especially during critical P1 incidents.
• Communicator: You can translate complex technical jargon into actionable business insights for stakeholders.
• Fluent: Excellent command of both Greek and English (written and verbal) is essential for this role.

Benefits:
We offer a competitive base salary and benefits, directly dependent on the candidate’s qualifications and skills. The real excitement comes from working closely with a dynamic, smart, agile, and highly motivated team in a competitive and fast-paced environment.

Follow us on LinkedIn and stay updated on our latest news. Upstream is an equal-opportunity employer.

Upstream is an equal-opportunity employer. The Company does not discriminate on the basis of race, color, creed, pregnancy, religion, gender, national origin, age, disability, marital, or any other legally protected status. The Company also makes reasonable accommodations for disabled employees. Finally, the Company prohibits the harassment of any individual based on their protected status. This policy applies to all areas of personnel actions including recruitment, hiring, training, promotion, compensation, benefits, transfer,and social and recreational programs